Merge pull request #271 from glyptodon/check-once

GUAC-1305: Only test for supported images when guacImage is initially loaded. No need to retest.

guacamole/src/main/webapp/app/client/services/guacImage.js

@@ -64,6 +64,31 @@ angular.module('client').factory('guacImage', ['$injector', function guacImage($
 
     };
 
+    /**
+     * Deferred which tracks the progress and ultimate result of all pending
+     * image format tests.
+     *
+     * @type Deferred
+     */
+    var deferredSupportedMimetypes = $q.defer();
+
+    /**
+     * Array of all promises associated with pending image tests. Each image
+     * test promise MUST be guaranteed to resolve and MUST NOT be rejected.
+     *
+     * @type Promise[]
+     */
+    var pendingTests = [];
+
+    /**
+     * The array of supported image formats. This will be gradually populated
+     * by the various image tests that occur in the background, and will not be
+     * fully populated until all promises within pendingTests are resolved.
+     *
+     * @type String[]
+     */
+    var supported = [];
+
     /**
      * Return a promise which resolves with to an array of image mimetypes
      * supported by the browser, once those mimetypes are known. The returned
@@ -74,11 +99,8 @@ angular.module('client').factory('guacImage', ['$injector', function guacImage($
      *     by the browser.
      */
     service.getSupportedMimetypes = function getSupportedMimetypes() {
-
-        var deferred = $q.defer();
-
-        var supported = [];
-        var pendingTests = [];
+        return deferredSupportedMimetypes.promise;
+    };
 
     // Test each possibly-supported image
     angular.forEach(testImages, function testImageSupport(data, mimetype) {
@@ -108,13 +130,9 @@ angular.module('client').factory('guacImage', ['$injector', function guacImage($
     // When all image tests are complete, resolve promise with list of
     // supported formats
     $q.all(pendingTests).then(function imageTestsCompleted() {
-            deferred.resolve(supported);
+        deferredSupportedMimetypes.resolve(supported);
     });
 
-        return deferred.promise;
-
-    };
-
     return service;
 
 }]);